One day last fall, in the home freezer of Spencer Wells, there were these things: a large leg of lamb, a few quarts of milk, and underneath, DNA samples from 2,500 people in Central Asia. Wells is an anthropological geneticist and an energetic collector of DNA, especially Y chromosomes. He lived then in an old stone house outside Geneva, but he was raised in Lubbock, Texas. His own Y chromosome, like his name, hails from Connecticut—an ancestor was governor there in the 17th century. Before that, Wells’s chromosome came from southern England, and before that, maybe 30,000 years ago, it came from Central Asia. From then and there to here and now, it was passed on, like an indelible stain, by a thousand fathers to a thousand sons, one after the other, until it ended up in Wells’s father, a Lubbock lawyer, and then in Wells.
The DNA samples in ...
